Here are all the commands you can say to Cortana.

The following text has been taken from Preview Forums on Xbox website. All the credit goes to Xbox.

To get started you can just say “Hey Cortana”. You can also launch Cortana from Snap Center in the Guide, or from My Games & Apps.

Cortana works with headsets. If you don’t have a Kinect just plug in a headset and start using speech on your console. You’ll notice a new microphone icon in the top right corner of Home dashboard which indicates when a microphone is connected and available for use with Cortana.

Cortana also understands you when you speak naturally, and will recognize commands you’re already familiar with. Just say “Hey Cortana” instead of “Xbox” for commands you already use. For instance you can say “Hey Cortana, go home” in place of “Xbox go home”.

Things To Try

Launch a game or app by saying “Hey Cortana, open {game/app name}” or something fun like “Hey Cortana, let’s play {game name}”.

Check on what a friend is up to without pausing your game by saying “Hey Cortana, what is {friend name} up to?”

Invite a friend to a party with a single phrase by saying “Hey Cortana, invite {friend name} to a party. Search the web with “Hey Cortana, search the web for Xbox One”.

Known issues
It’s early for Cortana on Xbox One and we’ll continue to make improvements and build new features. We’re still tuning Cortana, so please bear with us, and be sure to report issues via Report a problem!

If Cortana doesn’t hear you the first time, you can usually try saying the phrase again.

In some cases Cortana won’t recognize the name of any game or app (ie. “Hey Cortana open Netflix”). This is an issue we’re working to address, so please use Report a problem if you encounter it.

Sometimes short commands take longer than they should to be recognized (ie. “Hey Cortana mute”, “Hey Cortana pause”). “Hey Cortana snap TV” sometimes launches Movies & TV, rather than TV, until you say “1” or “2”. “Hey Cortana turn off the Xbox” … “Yes” in UK, FR, IT, DE, and ES sometimes gets stuck on the confirmation and fails.